U.S. patent number 4,990,251 [Application Number 07/376,135] was granted by the patent office on 1991-02-05 for resilient sealing ring.
This patent grant is currently assigned to Gambro Dialystoren GmbH & Co. KG. Invention is credited to Roland Antoni, Joachim Lutterbeck, Gerd Ott, Herbert Raabe, Kurt Spranger, Josef Volm.
United States Patent |
4,990,251 |
Spranger , et al. |
February 5, 1991 |
**Please see images for:
( Certificate of Correction ) ** |
Resilient sealing ring
Abstract
Resilient sealing rings are disclosed including an annular ring
of resilient material having a cross-sectional configuration so
that when not compressed the cross section of the sealing ring
extends substantially longitudinally and when compressed between
two parallel sealing surfaces the sealing ring bends so that the
longitudinal ends approach each other. This provides acceptable
compression force between the parallel sealing surfaces over an
extended range of deformation particularly as compared to
conventional O-rings. The use of such sealing rings in filtration
and/or diffusion devices is also described, particularly in
diffusion devices including a bundle of hollow fibers arranged
longitudinally within a housing in which the fiber ends are
embedded in end walls and in which a lid including an inlet or
outlet for fluid which is intended to flow through the hollow
fibers covers the end wall and in which these resilient sealing
rings are positioned between the outside of the end walls and the
inside of the lid.
Inventors: |
Spranger; Kurt (Ammerbuch,
DE), Antoni; Roland (Hechingen-Boll, DE),
Lutterbeck; Joachim (Hechingen, DE), Ott; Gerd
(Burladingen, DE), Raabe; Herbert
(Haigerloch-Stetten, DE), Volm; Josef
(Haigerloch-Owingen, DE) |
Assignee: |
Gambro Dialystoren GmbH & Co.
KG (DE)
|
Family
ID: |
20372846 |
Appl.
No.: |
07/376,135 |
Filed: |
July 6, 1989 |
Foreign Application Priority Data
Current U.S.
Class: |
210/321.8;
210/321.89; 210/500.23 |
Current CPC
Class: |
B01D
63/02 (20130101); B01D 63/021 (20130101); F16J
15/024 (20130101); A61M 1/16 (20130101); B01D
2313/04 (20130101); B01D 2313/21 (20130101) |
Current International
Class: |
B01D
63/02 (20060101); F16J 15/02 (20060101); A61M
1/16 (20060101); B01D 063/04 () |
Field of
Search: |
;210/232,321.6,321.64,321.72,321.77,321.78,321.79,321.8,321.81,321.87,321.88 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sever; Frank
Attorney, Agent or Firm: Lerner, David, Littenberg, Krumholz
& Mentlik
Claims
We claim:
1. A diffusion/filtration device comprising
a housing defining a longitudinally extending internal chamber
including a first end and a second end,
a bundle of semi-permeable hollow fibers disposed within said
internal chamber, said hollow fibers extending longitudinally from
said first end of said housing to said second end of said housing,
said hollow fibers having an outer surface and a first end and a
second end corresponding, respectively, to said first end and said
second end of said housing,
lid means for attachment to said first end of said housing, said
lid means including fluid communication means for providing fluid
to or withdrawing fluid from said first end of said internal
chamber,
end wall means supporting said first end of said hollow fibers
within said internal chamber so as to sealingly separate said first
end of said hollow fibers from said outer surface of said hollow
fibers between said first and second ends thereof, and
sealing ring means for providing acceptable compression force
between said end wall means and said lid means over an extended
range of deformations, said sealing ring means comprising an
annular ring of resilient material having a cross-sectional
configuration such that in its uncompressed condition said sealing
ring has a substantially longitudinally extending configuration
between first and second ends thereof including a longitudinal
dimension which is greater than its transverse dimension, whereby
upon being compressed between said end wall means and said lid
means said sealing ring bends in a manner such that said first and
second ends approach each other.
2. The diffusion/filtration device of claim 1 wherein said sealing
ring bends in a manner such that said first and second ends
approach each other at a location external to said sealing ring,
whereby upon being compressed between said lid means and said end
wall means and a third outer sealing surface substantially
perpendicular to said lid means and said end wall means said
sealing ring presents a concave configuration facing said third
sealing surface.
3. The diffusion/filtration device of claim 1 wherein in said
uncompressed condition said substantially longitudinally extending
configuration includes an arcuate shape, thereby providing concave
and convex outer surfaces, with said concave outer surface facing
outwardly from said ring.
4. The diffusion/filtration device of claim 1 wherein in said
uncompressed condition said substantially longitudinally extending
configuration includes a pair of concave outer surfaces, whereby
upon being compressed between said two parallel sealing surfaces
one of said concave outer surfaces of said sealing ring becomes
substantially planar.
5. The diffusion/filtration device of claim 1, said sealing ring
having a cross-sectional configuration such that upon being
compressed between said means and said end wall means said sealing
ring bends into a compressed configuration in which the compression
force increases gradually at a first rate and above a predetermined
compression force said compression forces increase at a second
rate, said second rate being accelerated with respect to said first
rate.
6. The diffusion/filtration device of claim 5 wherein as said
sealing ring is being bent into said compressed configuration said
compression force increases at a third rate, said third rate being
accelerated with respect to said first rate.
7. The diffusion/filtration device of claim 6 wherein the
relationship of said compression force to the deformation of said
sealing ring is substantially as shown in FIG. 5 hereof.
8. The diffusion/filtration device of claim 5 wherein said
cross-sectional configuration is such that in its uncompressed
condition said sealing ring has a substantially longitudinally
extending configuration between first and second ends thereof
including a longitudinal dimension which is greater than its
transverse dimension.
9. The diffusion/filtration device of claim 8 wherein upon being
compressed between said lid means and said end wall means said
sealing ring includes a concave surface facing outwardly from said
sealing ring.
10. The diffusion/filtration device of claim 9 wherein said lid
means has a cup-shaped configuration including peripheral flange
means adapted to be attached to the external surface of said
housing at said first end thereof.
11. The diffusion/filtration device of claim 10 wherein said
peripheral flange means of said lid means is attached to said first
end of said housing by a method selected from the group consisting
of welding, gluing and screw means.
12. The diffusion/filtration device of claim 9 wherein said sealing
ring comprises an elastomeric material.
13. The diffusion/filtration device of claim 12 wherein said
sealing ring comprises rubber.
Description
FIELD OF THE INVENTION
The present invention relates to a seal. More particularly, the
present invention relates to a sealing ring of resilient material.
Still more particularly, the present invention relates to a sealing
ring which is intended to be compressed between two preferably
flat, parallel surfaces. Still more particularly, the present
invention relates to seals which are preferably intended to be used
in filtration and/or diffusion devices, in particular those, for
example, as shown in U.S. Pat. application Ser. No. 07/237,514
filed on Aug. 26, 1988, pending and U.S. Pat. No. 07/237,504 filed
on Aug. 26, 1988, pending which devices employ a bundle of hollow
fibers arranged longitudinally within a housing and in which the
ends of the fibers are embedded in end walls with the sealing ring
positioned between the outside of at least one of the end walls and
a lid which has an inlet and/or an outlet for liquid which is
intended to flow through the hollow fibers in the bundle.
BACKGROUND OF THE INVENTION
In various filtration and diffusion devices, including those in the
above-identified U.S. patent applications, these devices generally
have a sealing ring which is in the form of an O-ring arranged
between an end wall and a cup-shaped lid member therefor. It has
been found in practice, however, that it is extremely difficult to
provide exactly the required degree of tightening pressure in these
devices when using such O-rings. This is particularly true when the
lid is to be welded to the housing. Therefore, in order to obtain
the desired degree of tightening pressure the lid must be placed in
a special position regarding the housing within extremely narrow
limits.
One type of sealing ring which is disclosed in the prior art is
shown in French Patent No. 2,088,735. However, this type of sealing
ring cannot provide the improved deformation in response to various
deformation forces over a wide range thereof. Another type of
sealing ring is disclosed in Swedish Patent No. 392,640. In this
case, as with the aforementioned French patent, it includes an
inwardly directed concave surface. Furthermore, the sealing ring is
not compressed between a pair of parallel surfaces, but is
compressed by a sloping surface, which thus provides
characteristics of deformation in response to deformation forces
which are limited to deformation by bending in only a small portion
of the sealing ring, with the shape of the sealing ring maintained
relatively constant by the shape of the housing within which it is
maintained. It is, therefore, an object of the present invention to
solve these prior difficulties which have become rather common for
a number of different technical fields. Thus, it will be understood
that particular advantage can be achieved by using the seals of
this invention in connection with these types of filtration and/or
diffusion devices, although one of ordinary skill in this art will
recognize that these seals can be used advantageously for other
purposes.
SUMMARY OF THE INVENTION
In accordance with the present invention the applicants have
discovered a sealing ring comprising an annular ring of resilient
material which has a cross-sectional configuration such that in its
uncompressed condition the sealing ring has a substantially
longitudinally extending configuration between first and second
ends thereof including a longitudinal dimension which is greater
than its transverse dimension, whereby upon being compressed
between two parallel sealing surfaces the sealing ring bends in a
manner such that the first and second ends approach each other and
provide acceptable compression force between the parallel sealing
surfaces over an extended range of deformations.
In accordance with a preferred embodiment of the sealing ring of
the present invention the sealing ring bends in a manner such that
the first and second ends approach each other in a direction
external to the sealing ring, whereby upon being compressed between
the two parallel sealing surfaces and a third outer surface which
is substantially perpendicular to those parallel surfaces, the
sealing ring presents a concave configuration facing the third
sealing surface.
In a preferred embodiment of the sealing ring of the present
invention, in its uncompressed condition the substantially
longitudinally extending configuration includes an arcuate shape,
thereby providing concave and convex outer surfaces, with the
concave outer surface facing outwardly from the sealing ring.
In another embodiment of the sealing ring of the present invention
in its uncompressed condition the substantially longitudinally
extending configuration includes a pair of concave outer surfaces,
whereby upon being compressed between the two parallel sealing
surfaces one of the concave outer surfaces becomes substantially
planar.
In accordance with another embodiment of the present invention
applicants have discovered a sealing ring comprising an annular
ring of resilient material having a cross-sectional configuration
such that upon being compressed between two parallel sealing
surfaces the sealing ring bends into a compressed configuration in
which the compression force increases gradually at a first rate and
above a predetermined compression force the compression force is
increased at a second rate which is accelerated as compared to the
first rate. In a preferred embodiment, as the sealing ring is being
bent into its compressed configuration, the compression force
increases at a third rate which is also accelerated as compared to
the first rate. In a highly preferred embodiment the relationship
of the compression force to the deformation of the sealing ring is
substantially as shown in FIG. 5 hereof.
In accordance with another embodiment of the sealing ring of the
present invention, the cross-sectional configuration of the sealing
ring is such that in its uncompressed condition the sealing ring
has a substantially longitudinally extending configuration between
first and second ends thereof which includes a longitudinal
dimension which is greater than its transverse dimension.
In accordance with another embodiment of the present invention,
applicants have also discovered a diffusion/filtration device,
which can preferably be such a device for dialysis, hemofiltration,
hemodiafiltration or oxygenation, and which comprises a housing
defining a longitudinally extending internal chamber including a
first end and a second end, a bundle of semi-permeable hollow
fibers disposed within the internal chamber, the hollow fibers
extending longitudinally from the first end of the housing to its
second end, and having an outer surface and a first end and a
second end which correspond, respectively, to the first and second
ends of the housing, lid means for attachment to the first end of
the housing, the lid means including fluid communication means for
providing fluid to or withdrawing fluid from the first end of the
internal chamber, end wall means supporting the first end of the
hollow fibers within the internal chamber to sealingly separate the
first end of the hollow fibers from the outer surface of the hollow
fibers between the first and second ends thereof, and a sealing
ring disposed between the end wall means and the lid means and
comprising an annular ring of resilient material having a
cross-sectional configuration such that in its uncompressed
condition the sealing ring has a substantially longitudinally
extending configuration between first and second ends thereof
including a longitudinal dimension which is greater than its
transverse dimension, whereby upon being compressed between the end
wall means and the lid means the sealing ring bends in such a
manner that the first and second ends approach each other.
In a preferred embodiment the lid means has a cup-shaped
configuration including a peripheral flange which is adapted to be
attached to the external surface of the first end of the housing,
and preferably this is done by welding, glueing or screwing the lid
means to the housing. In a preferred embodiment the sealing ring is
an elastomeric material such as rubber.
It can be seen that the sealing ring of the present invention has a
form such that as it is compressed it quickly reaches a knicking or
bending position, in the area defined by region I in FIG. 5, from
which the compression force increases slowly as compared with the
initial state of compression, in the area defined by region II in
FIG. 5, eventually reaching a position from which the compression
force once again increases at a more rapid rate, in the area
defined by region III in FIG. 5. By employing such a sealing ring
it is now possible to alter the position of the lid vis-a-vis that
of the housing particularly in the types of filtration/diffusion
devices mentioned above within rather wide limits and at the same
time still obtain small changes of the compression force as is
discussed in more detail below, particularly in reference to the
drawings.
In the above-described preferred embodiment of the sealing ring of
the present invention in which a third outer sealing surface
enclosing the sealing ring is employed, a liquid under pressure
within the sealing ring will tend to press the sealing ring against
that third sealing surface, thus providing an improvement in the
tightness of the seal provided by the sealing ring in that the same
liquid pressure will provide increased sealing pressure at the same
time against the first two parallel sealing surfaces perpendicular
to this third sealing surface.
In accordance with the embodiment of the sealing ring of the
present invention in which a concave outer surface is provided
directed against the third sealing surface, yet another advantage
is realized in that parallel sealing is obtained along two parallel
lines at the third sealing surface which is parallel to the two
opposed sealing lines against the first and second parallel sealing
surfaces.
In accordance with a preferred embodiment of the sealing ring of
the present invention, it has a configuration prior to compression
such as that shown in FIG. 3, which can be a boomerang or C-shaped
configuration. In this embodiment the concave side of the sealing
ring is directed outwardly against the third sealing surface, and
in this manner a convex side of the sealing ring is obtained
directed inwardly or toward the center of the sealing ring. If this
convex side of the sealing ring is to be exposed to an inner
pressure, it will be more or less flattened or planar, which is
advantageous especially when the liquid within the sealing ring is
a perishable liquid such as blood. This tendency of this preferred
sealing ring can be further strengthened by including an
indentation (see FIG. 4) on the convex side of the sealing ring,
i.e., one having a form such that this side of the sealing ring
will obtain an essentially flat form perpendicular to the first and
second parallel sealing surfaces in the sealing position of the
sealing ring.
As is also mentioned above, significant advantages are realized
when the sealing ring of the present invention is used as part of a
filtration and/or diffusion device as discussed above, such as a
dialyzer. As is discussed above, the sealing ring in this case can
have a construction such that it exhibits very gentle influences on
the liquid, such as blood, passing through the sealing ring. In
comparison with normal O-rings, the typical wedge-formed gaps above
and below the sealing ring where it contacts the first and second
substantially parallel surface is not obtained. As is also
mentioned above, because of this configuration the lid for the
filtration/diffusion device can be manufactured with far greater
tolerances than has previously been the case, and this is
particularly true for lids which are intended to be welded to the
housings thereof. Under normal circumstances, such a lid which is
intended to be welded to the housing must be made within very
narrow tolerances since the welding machine restricts the
possibility of placing lids of different dimensions in different
positions so as to provide a desired degree of tightening
pressure.
The resilient sealing ring of the present invention is preferably
made of rubber or a similar elastomeric material. However, other
materials can be used if they are provided with a form and
resiliency so as to provide the above-described functions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial, partially sectional, elevational view of a
filtration and/or diffusion device including the sealing ring of
the present invention;
FIG. 2 is a partial, partially sectional, elevational view of a
modified filtration and/or diffusion device including a sealing
ring according to the present invention;
FIGS. 3a through 3c are cross-sectional, elevational views of a
sealing ring according to the present invention subjected to three
different degrees of compression;
FIGS. 4a through 4c are cross-sectional, elevational views of
another embodiment of the sealing ring of the present invention
exposed to three different degrees of compression;
FIG. 5 is a graphical representation showing the deformation for
various deformation forces for a normal O-ring and for the sealing
ring according to the present invention; and
FIG. 6 is a graphical representation showing the deformation for
various deformation forces for a normal O-ring and for the type of
sealing ring shown in French Patent No. 2,088,735.
DETAILED DESCRIPTION
Turning to the Figures, in which like numerals refer to like
elements thereof, FIG. 1 shows one end of a filtration and/or
diffusion device of the type disclosed in the above-identified U.S.
patent application Ser. No. 07/237,504, but provided with a sealing
ring 17 according to the present invention. The device consists of
a bundle of hollow fibers 1 arranged in a housing 2 with the ends
embedded in a potting material providing an end, wall 3. The ends
of the fibers have been opened by a transverse cut providing an end
surface 13, as described, for example, in U.S. Pat. No. 4,689,191.
The device is provided with an inlet and/or outlet 4 and a second
outlet and/or inlet 15 for first and second liquids, respectively.
Normally, the other end of the device (not shown in the drawings)
is given an identical form. However, if the device is intended to
be used only for filtration, a second nipple 4 is unnecessary.
The nipple 4 serving as an inlet or an outlet is arranged on an
enlarged portion 7 of the housing 2. Within this enlarged portion
7, there is located a ring 6 in a groove 8, the ring 6 including an
inner flange 9 which serves to reduce the contact area between the
end wall 3 and the housing 2, as is described in more detail in the
above-identified U.S. patent application. For that purpose the ring
6 is made of a material which has a coefficient of adhesion with
regard to the material of the end wall which is less than the
coefficient of adhesion of the housing with regard to the same
material of the end wall.
The inlet and/or outlet 15 is arranged in a lid 14 which is
attached to the enlarged portion 7 of the housing 2 by a welding
18. Alternatively, it may be attached by glue.
The two above-mentioned parallel sealing surfaces are provided by
end surface 13 of the fiber bundle 1 on the one hand and by the
inside 16 of the lid 14 on the other. The third sealing surface is
designated 19, and is provided by the inside of the flange of the
lid 14.
Referring next to FIG. 2, there is shown a more conventional
filtration and/or diffusion device modified in accordance with the
present invention. Many details of FIG. 2 are essentially identical
to corresponding details of FIG. 1, and have therefor been given
the same reference numerals. Consequently, the device according to
FIG. 2 comprises a bundle of hollow fibers 1 within a housing 2
with an enlarged portion 7 to which a lid 14 is attached. The
attachment is, however, not made by glue or welding, but in this
case by means of a screw connection 18a. The end surface of the
fiber bundle has been designated 13, and the fiber ends have been
opened in the same manner as is described above. The device
includes inlets and/or outlets 4 and 15, and a sealing ring 17
according to the present invention in the same way as the device
described above. An end wall 3a made by a potting material,
contrary to the end wall 3, has a strong attachment to the inner
wall of the enlarged portion 7 of the housing 2.
In order to explain the function of the sealing ring 17, reference
is made to FIGS. 3a to 3c, FIGS. 4a to 4c, and to FIG. 5. In an
uncompressed condition the ring may, for example, have
cross-sectional configuration as shown in either FIG. 3c or FIG. 4c
with the upper side being intended to be directed inwardly against
the liquid passing through the inlet and/or outlet 15 in both
cases.
FIGS. 3b and 4b show the same cross-sections through the sealing
ring in an ideal sealing position. The flat surface 21 shown in
FIG. 4b of the modified sealing ring 17' according to FIGS. 4a to
4c is provided by means of the indentation 20 shown in FIG. 4c.
By means of the application of further compression the positions
shown in FIGS. 3a and 4a are eventually reached, and a good seal is
still provided thereby. However, thereafter, further compression
will rapidly increase the deformation force in an unacceptable
manner.
FIG. 5 shows the deformation as a function of the deformation force
for a normal O-ring on the one hand, and a sealing ring according
to the present invention on the other. This comparison is presented
in the form of an example. By using different materials and
dimensions, the figures in FIG. 5 will, of course, vary. In the
example shown, a normal O-ring may be used within a range of
operation of between 0.8 and 1.6 mm, corresponding to deformation
forces of between 75 and 300 N. A sealing ring according to the
present invention, however, reaches an acceptable sealing pressure
much more rapidly, i.e., after about 0.4 mm, and the deformation
force is still below the acceptable 300 N up to a deformation of
about 2.5 mm. Consequently, according to the present invention, it
is possible to use lids, housings, sealing rings and welding tools
or other tools for attachment, and to do so within wide
tolerances.
FIG. 6 shows the deformation as a function of the deformation force
for a normal O-ring and for the sealing ring shown in French Patent
No. 2,088,735. As can be seen therein, and particularly as compared
to the characteristic curve of the sealing ring of the present
invention as shown in FIG. 5, the characteristic curves in FIG. 6
show similar slow decreases in the force at low deformations which
then increase rapidly at higher deformations. Thus, in their area
of operation, they show deformations which mainly relate to
deformation by bending, somewhat like that in area II of the
sealing ring of the present invention. They do not, however,
exhibit the overall characteristics of the sealing rings of the
present invention, including that of the areas designated I and III
in FIG. 5 hereof.
Although the invention herein has been described with reference to
particular embodiments, it is to be understood that these
embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims.
* * * * *